A synthetic resin foam is variously used for an adiabatic material, a packaging material, a buffer material, an interior material, and the like, due to small weight, and superior adiabatic and buffer effects thereof. There are various resins such as polystyrene, polyethylene, polypropylene, and the like, as a synthetic resin used here. However, these incur pollution problems at the time of disposing thereof, and thus, are being requested to be changed into eco-friendly products in the long term.
Polypropylene carbonate, which is a product prepared by using carbon dioxide as a raw material, is an eco-friendly product having an effect of reducing about 50% in costs of petrochemical raw material, as compared with a product produced from the petrochemical raw material, and does not cause harmful gases generated from the existing synthetic resins even at the time of incineration. However, when this eco-friendly polypropylene carbonate is alone foamed, it shrinks at room temperature after foaming, and thus, fails to retain an initial shape.
Therefore, an expandable polypropylene carbonate, which is eco-friendly, substituted for the existing synthetic resin foam, and has a shape retention performance and dimensional stability at a use temperature after foaming, is being requested in view of economical and environmental aspects.